Sewing machine drive mechanism



Oct. 17, 1967 R. J. ROSS SEWING MACHINE DRIVE MECHANISM I5 Sheets-Sheet 1 Filed Sept. 1, 1965 INVENTOR. Roger J Ross WITNESS ATTORNEY Oct. 17, 1967 955 3,347,191

SEWING MACHINE DRIVE MECHANISM Filed Sept. 1, 1965 3 Sheets-Sheet 2 rd 5. u

JNVENTOR.

Roger J. Ross WITNESS A T TOR/V5 Y Oct. 17, 1967 R. J. ROSS SEWING MACHINE DRIVE MECHANISM a Sheets-Sheet 5 Filed Sept. 1, 1965 145 [4 43 Fig. 4.

rwfis R m s y w m M R W R .m J 2 r w w 0 R M Y B WITNESS United States Patent Ofilice 3,3471% Patented Oct. 17, 1967 3,347,191 SEWENG MAQHINE DRIVE MECHANISM Roger J. Ross, Dover, NHL assignor to The Singer Company, New York, N.Y., a corporation of New Jersey Filed Sept. 1, 1965, Ser. No. 484,175 Claims. (Cl. 112-220) This invention relates to a novel and improved lock stitch sewing mechanism, and more particularly, to a simple and effective actuating mechanism for the operating instrumentalities of a sewing machine.

It is an object of this invention to provide a lock stitch sewing machine of which all of the operative mechanisms, i.e., needle, looptaker, take-up, and feed mechanisms are organized so as to be actuated in response to a single motion generating element.

A more specific object of this invention is to provide a lock stitch sewing machine of which all of the operative mechanisms are actuated upon rotation of a single eccentric in a manner which provides, in addition to simplicity and effectiveness, a drive which will impart interrelated stitch forming motion to the sewing machine mechanisms in each direction of rotation of the single operating eccentric.

A further object of this invention is to provide a novel operator influenced clutch means for selectively coupling or uncoupling the single operating eccentric to a drive means such as a treadle, electric motor, or the like.

With the above and additional objects and advantages in View as will hereinafter appear, this invention comprises the devices, combinations and arrangements of parts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment in which:

FIG. 1 represents a side elevational view of a sewing machine embodying this invention,

FIG. 2 represents a head end elevational view of the sewing machine of FIG. 1, with a portion broken away to illustrate the bobbin winding device,

FIG. 3 is a vertical cross sectional view of the sewing machine taken substantially along line 3--3 of FIG. 1,

FIG. 4 represents a bottom plan view of the sewing machine of FIG. 1, and

FIG. 5 is a perspective view of the actuating mechanism of the sewing machine of FIGS. 1-4 including portions of the stitch forming and work feeding mechanisms.

Referring to the drawings, the sewing machine frame comprises a bed plate 11 to which a depending wall 12 is secured at the free extremity and a pair of depending legs 13 are secured at the other extremity. Rising from the bed plate is a unitary supporting plate indicated generally at 14 which includes a standard 15, a bracket arm 16 cantilevered over the bed plate, and a head portion 17. The supporting plate may be formed integrally with the bed plate, welded thereto, or attached thereto by fastening screws as desired.

Forced fit in a transverse bore 20 in the supporting plate 1 4 at the juncture of the standard and bracket arm is a bushing 21 in which is journaled a stud shaft 22. Fast on the stud shaft at the rear of the machine is a pulley member 23 adapted to accommodate a belt from a treadle or electric drive motor (not shown). Loose on the stud shaft 22 at the front of the machine is an eccentric 24 which provides the single motion generating element for all of the operative mechanism of the sewing machine. The eccentric 24 is formed with a radial flange 25 in which is formed a plurality of apertures 26 each spaced a uniform distance radially from the axis of the stud shaft. A handwheel 27 is carried on the free end of the stud shaft, the handwheel having a hub 28 adjacent to the eccentric flange drilled and tapped for a set screw 29 by which the handwheel is made fast to the stud shaft.

In the exposed face, the handwheel is formed with an outer counterbore 30' of large diameter and with an additional inner counterbore 31 of smaller diameter. Secured by nuts 32 threadedly engaging the extremity of the stud shaft is a bracket 33 having diametrically opposed and outwardly extending ears 34 disposed within the inner counterbore 31 of the handwheel. Arranged in the outer counterbore 30 of the handwheel is an annular disk or wobble plate 35 to which is secured a bracket 36- having diametrically opposed and inwardly extending cars 37 which are pivotally connected by pins 38 to the bracket cars 34 on the stud shaft. The bracket 36 on the disk 35 is also formed with a finger 39 which engages an annular recess 40 formed in a clutch pin 41 which is slidable in a bore 41 in the handwheel hub, the bore 41' being radially spaced from the axis of the stud shaft a distance equal to that of the apertures 26 in the eccentric flange.

When the disk or wobble plate 35 is depressed at one side of the pivot pins 33, which may be marked bobbin as illustrated in FIG. 1, the disk will be canted so as to withdraw the clutch pin 41 from the eccentric flange so that the stud shaft will turn without rotating the eccentric. Such a position of parts is desirable, for instance, for winding bobbins Without operating the stitch forming instrumentalities. When the disk or wobble plate 35 is depressed at the opposite side of the pivot 38, which may be marked sew as illustrated in FIG. 1, the disk will be canted so as to urge the clutch pin toward the eccentric flange so as to enter one of the apertures 26 therein when alignment occurs thus to lock the eccentric for rotation with the stud shaft 22. The clutch pin 41 may be formed with a shallow annular groove 42 cooperating with an annular spring Wire 43 seated in an annular notch 44 formed in the handwheel hub frictionally to deter accidental movement of the clutch pin out of engagement with the eccentric flange.

The bobbin winder, as illustrated in FIGS. 1, 2, and 3 comprises a unit adapted to be carried at the juncture of the standard 15 and bracket arm 16. The bobbin winding unit includes a bushing assembly 50 for two parallel endwise movable shafts 51 and 52. The upper shaft 51 constitutes the bobbin winding shaft and is rotatable as well as endwise movable. A spring '53 within the bushing assembly biases the bobbin winding shaft endwise towards the right as viewed in FIG. 2 and urges a rubber wheel 54 fast on the bobbin winding shaft away from engagement with the inside face of the pulley 23. At the opposite extremity, the bobbin winding shaft carries a collar 55 formed with a shallow seat 56 adapted to accommodate a bobbin. A latch lever 57 pivoted at 58 on the bushing assembly 50 extends forwardly adjacent to the collar 55 and is there formed with a thread sensing finger 59. A latch pin 60 on the lever 57 cooperates with a shoulder 61 on the bobbin winding shaft to hold the rubber wheel 54 against the pulley 23 until sufiicient thread is wound on a bobbin to release the latch.

The lower shaft 52 carries a sleeve 62 which constrains a coil spring 63 biasing the shaft 52 to the left as viewed in FIG. 2. At the front of the machine, the shaft 52 carries an upwardly open box-like container 64 which constrains a bobbin in place in the shallow seat 56 of the collar 55 on the bobbin winding shaft.

For operating the stitch forming instrumentalities, a bell crank lever 70 is fulcrummed on a shouldered screw 71 threaded into the supporting plate 14. The bell crank includes an arm 72 extending alongside the bracket arm 16 and an arm 73 depending alongside the standard. An aperture 74 in the arm 73 accommodates the drive eccentric and is preferably formed with spaced outturned cars 75 which embrace diametrically opposite sides of the eccentric.

At the free end of the bell crank arm 72 is pivoted a depending link 76 pivotally connected, in turn, to a needle bar 77 of rectangular cross sectional shape endwise slidable in a vertical slot 78 formed in the head 17. A needle clamp 79 on the needle bar serves to secure a conventional needle 80 therein.

A block 81 secured by screws 82 to the head 17, is formed with a gib 83 which overlies the slot 78 to constrain the needle bar in the slot 78. The block 81 also carries a needle thread tensioning device 84 and a bracket 85 in which is carried a thread guide 86 and a light thread tensioning device 87.

The needle thread take-up is provided by a take-up lever 90 fulcrumed on a shouldered screw 91 which passes through a clearance slot 92 in the bell crank lever 70. A roller 93 secured on the take-up lever enters a slot 94 formed in the bell crank arm 72 so as to be driven in response to oscillation of the bell crank. At the free extremity, the take-up lever is formed with a thread engaging loop 95. The needle thread is thus directed from a spool on a spool pin 96 on the supporting plate 14, to the needle thread tensioning device 84, the thread guide 86, the thread engaging lop on the take-up, and hence to the light tension device 87 and to the needle.

FIGS. 2 and 4 of the drawings illustrate the loop taker which is indicated generally at 100. The loop taker takes the form of a circular shuttle journaled in an arm 101 which is pivoted on a bolt 102 beneath the bed plate 11. A shuttle driver 103 is carried on a stud shaft 104 in the arm 101 which stud shaft carries a pinion 105 meshing with an arcuate gear segment 106 adjustable about the.

bolt 102 and secured in place by the fastening screw 107 beneath the bed plate. As the arm 101 is oscillated therefore, the shuttle 100 will be imparted a combination of two motions, turning movement about its central axis and oscillatory motion with the arm 101 about the axis of the bolt 102. Any particular point on the shuttle, therefore, will partake of a form of epicycloidal motion.

For imparting oscillatory movement to. the shuttle carrying arm 101 in timed relation with the endwise needle reciprocation, a roller 110 which is carried on the depending bell crank arm 72 is embraced by inturned ears 111 formed on a lever 112. The lever 112 is fulcrumed on a shouldered screw 113 threaded into a spacing block 114 secured by bolts 115 to the standard 15. Motion of the lever 112 is transferred by means of a link 116 to a slide plate 117 which is constrained in a slot 118 beneath the bed plate 11 by a gib 119 as shown in FIG. 4. A link 120 pivotally connected to a depending ear 121 on the slide plate 117 is pivoted by the screw 122 to the shuttle carrying arm 101.

The bell crank lever 70 and the linkages connected.

thereto provide a first. actuating mechanism driven by the eccentric 24 for operating the needle bar 77 the looptaker 100 and the needle thread take-up 90 with those interrelated motions required for the formation of stitches.

As illustrated in FIG. 2, the bed plate 11 is formed beneath the needle with an opening covered by a throat plate 131 which is formed with a needle aperture 132 and with slots 133 to accommodate a work feed dog 134. The feed dog is opposed by a conventional presser foot 135 carried by a presser bar 136 vertically slidable in the head 17 and biased downwardly by a presser spring 137. A pin 138 on the presser bar overlies a presser lifting cam lever 139 of which a finger grip extends rearwardly of the machine and may be turned to elevate the presser foot.

The feed dog 134 is secured by screws 140 to upturned arms 141 at the forward extremity of a sheet metalfeed bar 142. At the rearward extremity the feed bar is formed with spaced upturned arms 143 pivoted to spaced rock arms 144 formed on a feed advance rock frame 145 which is journaled between trunnion screws 146 threaded one in the depending wall 12 and the other in a depending 4 boss 147 beneath the bed. Oscillation imparted to the feed advance rock frame 145 will thus impart feed advance and return movements to the feed dog.

For imparting rising and falling motions to the feed dog, a feed lift rock frame 148 is journaled beneath the bed plate between trunnion screws 149 threaded one in the depending wall 12 and the other in a depending bo'ss 150. A rock arm 151 on the feed lift rock frame is pivotaly connected to a link 152 which is pivoted to and depends from one of the upturned arms 141 of the feed bar.

For imparting feed advance and return motion to the feed bar, a pitman which embraces the drive eccentric 24 is pivoted at 161 to a bell crank lever 162 fulcrumed at 163 on a boss 164 beneath the bed plate. Pivoted at 165 on the bell crank lever 162 is one end of a twisted link 166 which is pivotally connected to an oscillating bracket 167 fulcrumed beneath the bed plate on a shouldered screw 168. The bracket 167 comprises a flat metallic plate 169 and an arched metallic plate 170 rigidly secured together as by screws 171. The arched plate 170 sustains the fulcrum screw while the fiat plate 169 is formed with an arcuate slot 172. A link 173 pivoted on a fastening 174 to a rock arm 175 on the feed I advance frame 145 carries a headed screw 176 constrained in the arcuate slot 172 and the arcuate slot preferably has a center of curvature substantially coincident with the fastening 174. An adjusting link 177 is pivoted to the link 173 and pivoted to a clamp block 178 which together with a slide block 179 arranged in a slot 180 in the bed plate 11 may be secured in selected position by a thumb screw 181.

The eccentric 24 will impart oscillatory motion of constant amplitude to the bracket 167, and, the thumb screw may be used selectively to position the headed screw 176 on the link 173 along the arcuate slot 172 thus to determine the magnitude and direction of feed motion imparted to the feed dog. When the headed screw 176 is positioned directly beneath the fulcrum screw 168v no feed motion will occur. With any particular direction of rotation of the eccentric 24, positioning of the headed screw 176 to one side of the fulcrum screw will result in a forward feed while positioning of the headed screw on the opposite side will result in a rearward feed. The feed direction, however, may also be reversed simply by reversing the direction of rotation of the eccentric24.

For imparting feed lift motion to the feed bar, an arched bracket is secured by screws 186 to the lever 112 spanning the fulcrum screw 113. As illustrated in FIG. 1 a transverse slot 187 is formed in the arched bracket 185, the slot extending from a point in alignment with the axis of the fulcrum screw 113 toward one side thereof. Secured in selected position along the slot 187 by a clamp screw and thumb nut 188 is a link 189 pivotally connected to a lever 190 fulcrumed beneath the bed plate on a shouldered screw 191. The lever 190 makes a universal pivotal connection with a rock arm 192 on the feed lift rock frame 148 by means of a slot 193 formed in thelever and a spherical head 194 formed on the rock arm and arranged in the slot 193. When the clamp screw and thumb nut 188 position-the link 189 in axial alignment with the fulcrum screw 113 no feed lift motion will be imparted to the feed bar and the feed dog will move idly beneath the level of the throat plate. By selectively positioning the clamp screw and thumb nut along the slot 187 to one side of the axis of the fulcrum screw 113a feed lift motion will occur in proportion to the distance of the thumb nut from the axis of the fulcrum'screw. Thus any desired feed lift to suit the characteristics of the fabric being stitched may be readily attained and the operator may conveniently render the feed mechanism ineffective.

The pitman 160 and the bell crank lever 162 comprise a second actuating mechanism which is driven by the eccentric 24 and serves to impart fed motion to the work is feeding mechanism. Both the lever 70 of the first actuating mechanism and the lever 162 of the second actuating mechanism are imparted a simple harmonic motion from the eccentric 24 however, the oscillation of the levers 70 and 162 occurs with substantially 90 phase angle difference therebetween. FIG. 1 illustrates the manner in which such phase angle difference is derived. Indicated at xx in FIG. 1 is a plane containing the axes of the shaft 22 and of the fulcrum screw '71 of the bell crank lever 70. Indicated a y-y in FIG. 1 is a line drawn through the axis of the fulcrum screw 163 of the bell crank lever 162 and through the axis of the pivot screw 161 between the pitman 160 and the bell crank lever 162. It will be noted that the line y-y extends substantially perpendicular to the plane xx thus providing for a substantially 90 phase angle difference between the oscillatory motions of the levers 70 and 162. With this arrangement, the work feed advance motion will always occur while the needle is raised out of the work. Furthermore, if the phase angle difference is maintained at approximately 90, as in the embodiment illustrated in the drawings, the interrelationship will be such that the sewing machine will produce stitches regardless of the direction of rotation of the eccentric 24 with the only change resulting from reversal of direction of eccentric rotation being that the direction of work feed will be reversed.

Having thus set forth the nature of this invention, what I claim herein is:

1. In a sewing machine having a frame, and stitch forming instrumentalities carried on said frame including an endwise reciprocatory needle bar, a shiftably supported loop-taker, and a work feeding mechanism, drive means for said stitch forming instrumentalities comprising a shaft journaled in said frame, a single rotary actuator carried on said shaft, a first actuating mechanism including first means directly connected to and driven by said rotary actuator for operating said needle bar and loop-taker in timed relation in the formation of stitches, and a second actuating mechanism including second means directly connected to and driven by said rotary actuator in aproximately 90 phase angle difference from said first actuating mechanism for operating said work feeding mechanism.

2. In a sewing machine having a frame, and stitch forming instrumentalities carried on said frame including an endwise reciprocatory needle bar, a shiftably supported loop-taker, and a work feeding element shiftable in the direction of feed, drive means for such stitch forming instrumentalities comprising a driven shaft journaled in said frame, a single rotary actuator, means for connecting said rotary actuator to said driven shaft, a pair of driven levers fulcrumed on said frame, means separately interconnecting each of said pair of driven levers with said single rotary actuator for oscillation of said pair of levers with subsantially 90 phase angle difference therebetween upon rotation of said rotary actuator, linkage operatively connecting a first of said pair of levers to said needle bar and to said loop-taker for imparting interrelated stitch forming motion thereto, and linkage operatively connecting a second of said pair of levers with said work feeding element for imparting movements thereto in the direction of feed.

3. In a sewing machine having a frame, and stitch forming instrumentalities carried on said frame including an endwise reciprocatory needle bar, a shiftably supported loop-taker, and a drop feed device including a work feeding element, feed lift mechanism for raising and lowering said work feeding element into and out of operative work feeding position, and feed advance mechanism for shifting said feeding element in the direction of feed, drive means for said stitch forming instrumentalities comprising a driven shaft journaled in said frame, a single rotary actuator, means for connecting said rotary actuator to said driven shaft, a pair of driven levers fulcrummed on said frame, means separately interconnecting each of said pair of driven levers with said single rotary actuator for oscillation of said pair of levers with substantially phase angle difference therebetween upon rotation of said rotary actuator, linkage operatively connecting a first of said pair of levers to said needle bar, said loop-taker, and said feed lift mechanism, and linkage operatively connecting a second of said pair of levers with said feed advance mechanism.

4. In a sewing machine having a frame, and stitch forming instrumentalities carried on said frame including an endwise reciprocatory needle bar, a shiftably supported loop-taker, and a work feeding element shiftable in the direction of feed, drive means for said stitch forming instrumentalities comprising a driven shaft journaled for rotation on an axis in said frame, an eccentric, means for connecting said rotary actuator to said driven shaft, a first driven lever fulcrumed on said sewing machine frame on an axis parallel with said driven shaft axis, said axes defining a reference plane relatively to said sewing machine frame, a bifurcated eccentric embracing fork carried by said first driven lever, a second driven lever fulcrumed on said sewing machine on an axis parallel to said driven shaft, a pitman embracing said eccentric, pivot means interconnecting said pitman with said second driven lever, said pivot means and said second driven lever fulcrum intersecting a line disposed substantially perpendicular to said reference plane, linkage operatively connecting the first of said driven levers to said needle bar and to said loop-taker for imparting interrelated stitch forming motion thereto, and linkage operatively connecting the second of said driven levers with said work feeding element for imparting movements thereto in the direction of feed.

5. In a sewing machine having a frame, and stitch forming instrumentalities carried on said frame including an endwise needle bar, a shiftably supported loop-taker, and a work feeding mechanism, drive means for said stitch forming instrumentalities comprising a shaft journaled in said frame, a rotary member fixed on said shaft, a single rotary actuator freely journaled on said shaft adjacent to said rotary member, a first actuating mechanism including first means directly connected to and driven by said eccentric for operating said needle bar and loop-taker in timed relation in the formation of stitches, a second actuating mechanism including second means directly connected to and driven by said eccentric in approximately 90 phase angle difference from said first actuating mechanism for operating said work feeding mechanism, and operator influenced clutch means for securing said eccentric relatively to said shaft comprising a wobble plate pivoted to said shaft on an axis perpendicular to said shaft, a clutch pin slidably constrained in said rotary member substantially parallel to said shaft axis, means interconnecting said clutch pin with said wobble plate, and said eccentric being formed with at least one clutch pin accommodating aperture.

References Cited UNITED STATES PATENTS 194,995 9/1877 Cummins ll2220 1,100,497 6/1914 Seymour 112-215 2,144,801 1/1939 Hohmann 112-220 JORDAN FRANKLIN, Primary Examiner. H. H. HUNTER, Assistant Examiner. 

1. IN A SEWING MACHINE HAVING A FRAME, AND STITCH FORMING INSTRUMENTALITIES CARRIED ON SAID FRAME INCLUDING AN ENDWISE RECIPROCATORY NEEDLE BAR, A SHIFTABLY SUPPORTED LOOP-TAKER, AND A WORK FEEDING MECHANISM, DRIVE MEANS FOR SAID STITCH FORMING INSTRUMENTALITIES COMPRISING A SHAFT JOURNALED IN SAID FRAME, A SINGLE ROTARY ACTUATOR CARRIED ON SAID SHAFT, A FIRST ACTUATING MECHANISM INCLUDING FIRST MEANS DIRECTLY CONNECTED TO AND DRIVEN BY SAID ROTARY ACTUATOR FOR OPERATING SAID NEEDLE BAR AND LOOP-TAKER IN TIMED RELATION IN THE FORMATION OF STITCHES, AND A SECOND ACTUATING MECHANISM INCLUDING SECOND MEANS DIRECTLY CONNECTED TO AND DRIVEN BY SAID ROTARY ACTUATOR IN APPROXI- 